- #1

- 180

- 8

## Homework Statement

How much photon energy would be required to produce a proton-antiproton pair? Where could such a

high-energy photon come from?

## Homework Equations

[itex]E^{2} = (pc)^{2} + (E_{0})^{2}[/itex]

## The Attempt at a Solution

Since the photon is massless its energy is

[itex]E_{i}=pc[/itex]

The final energy is:

[itex]E_{f}^{2}=(pc)^{2}+(2m_{+}c^{2})^2[/itex]

and we know that energy and momentum are conserved, so:

[itex]E_{i}^{2}=E_{f}^{2}[/itex]

[itex](pc)^{2} = (pc)^{2}+(2m_{+}c^{2})^2[/itex]

but clearly, the mass of a photon is not zero, so how can this be?

edit-

## Homework Statement

## Homework Equations

## The Attempt at a Solution

Please.. Can someone fix this? This gets added at the end of my post every time I preview post. It has been doing this for years...